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Large-Area Silver-Coated Silicon Nanowire Arrays for Molecular Sensing Using Surface-Enhanced Raman Spectroscopy

Authors

  • Baohua Zhang,

    1. State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (PR China)
    2. Graduate School Chinese Academy of Sciences, Beijing 100039 (PR China)
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  • Haishui Wang,

    1. State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (PR China)
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  • Lehui Lu,

    Corresponding author
    1. State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (PR China)
    • State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (PR China).
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  • Kelong Ai,

    1. State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (PR China)
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  • Guo Zhang,

    1. State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (PR China)
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  • Xiaoli Cheng

    1. State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (PR China)
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  • Financial support from the “Hundred Talents Project” (Initialization Support) of the Chinese Academy of Sciences, the National Natural Science Foundation of China (Director Funds, no. 20845001), and the Program for Excellent Doctoral Thesis of the Chinese Academy of Sciences is gratefully acknowledged. Supporting Information is available online from Wiley InterScience or from the authors.

Abstract

A new and facile method to prepare large-area silver-coated silicon nanowire arrays for surface-enhanced Raman spectroscopy (SERS)-based sensing is introduced. High-quality silicon nanowire arrays are prepared by a chemical etching method and used as a template for the generation of SERS-active silver-coated silicon nanowire arrays. The morphologies of the silicon nanowire arrays and the type of silver-plating solution are two key factors determining the magnitude of SERS signal enhancement and the sensitivity of detection; they are investigated in detail for the purpose of optimization. The optimized silver-coated silicon nanowire arrays exhibit great potential for ultrasensitive molecular sensing in terms of high SERS signal enhancement ability, good stability, and reproducibility. Their further applications in rapidly detecting molecules relating to human health and safety are discussed. A 10 s data acquisition time is capable of achieving a limit of detection of approximately 4 × 10−6M calcium dipicolinate (CaDPA), a biomarker for anthrax. This value is 1/15 the infectious dose of spores (6 × 10−5M required), revealing that the optimized silver-coated silicon nanowire arrays as SERS-based ultrasensitive sensors are extremely suitable for detecting Bacillus anthracis spores.

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